ruby (extrat the ip address last login and sort them)

First I have a file derived from the last command in Linux. But I have hard time to figure out how to extract and sort every IP address and last command for each user. This actually how the file looks like:

frank    pts/5        192.220.128.18   Thu Dec 13 21:47   still logged in 
enha     pts/3        17.0.0.206       Thu Dec 12 21:09   still logged in
skr      pts/1        184.31.240.205   Thu Dec 19 18:57 - 21:18  (02:20)
skr      pts/6        182.31.40.205    Thu Oct 24 16:42 - 16:53  (00:10)
skr      pts/7        182.31.40.205    Thu Oct 24 15:35 - 15:42  (00:06)
frank    pts/6        177.31.20.205    Thu Avr 24 15:33 - 15:42  (00:08)
sama     pts/5        190.150.128.25   Thu Avr 25 15:03 - 17:03  (02:00)
ccorn    pts/3        100.10.128.27    Thu Sep 24 14:17 - 14:26  (00:08)

And this is the output I'm looking for:

UserName,Last Login,Total Logins,IP Address List
frank,Nov 13 21:47,2,192.220.128.18;177.31.20.205
skr,Dec 19 18:57,3,182.31.40.205;188.31.40.205
sama,Avr 25 15:03,1,190.150.128.2

i was able to count for example how may each user login but i could not figure the rest and sort them as expect to be this is what I done so far

frequencies = Hash.new(0)
login = []

lines =File.readlines("file.txt")
lines.each do |line|
login << line.split[0]

end
#p login

login.each do |user|
  frequencies[user] += 1
end
  p frequencies

and thanks in advance